Skip "test-rwlock1" when multithreading is disabled, which is the case
during bootstrapping on architectures not supported by GNU Mes.

Taken from upstream gnulib:
https://git.savannah.gnu.org/cgit/gnulib.git/commit/?id=fdff8bd09a7f053381f8bdb107ab5280b7c95959

diff --git a/gnulib-tests/test-rwlock1.c b/gnulib-tests/test-rwlock1.c
--- a/gnulib-tests/test-rwlock1.c
+++ b/gnulib-tests/test-rwlock1.c
@@ -21,6 +21,8 @@
 
 #include <config.h>
 
+#if USE_ISOC_THREADS || USE_POSIX_THREADS || USE_ISOC_AND_POSIX_THREADS || USE_WINDOWS_THREADS
+
 #include "glthread/lock.h"
 
 #include <errno.h>
@@ -151,3 +153,18 @@ main ()
       sleep (1);
     }
 }
+
+#else
+
+/* No multithreading available.  */
+
+#include <stdio.h>
+
+int
+main ()
+{
+  fputs ("Skipping test: multithreading not enabled\n", stderr);
+  return 77;
+}
+
+#endif

>
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<tr><td><span title='2020-02-16 23:31:08 +0100'>2020-02-16</span></td><td><a href='/guix/commit/gnu/services/shepherd.scm?id=8b9cad01e9619f53dc5a65892ca6a09ca5de3447'>services: shepherd: Spawn services with nothing but the PATH variable.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2019-10-06 14:45:35 +0200'>2019-10-06</span></td><td><a href='/guix/commit/gnu/services/shepherd.scm?id=63b0ce391f6ea79012fac893e933e39d7a16abbd'>services: shepherd: Compile service files.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2019-04-23 16:38:12 +0200'>2019-04-23</span></td><td><a href='/guix/commit/gnu/services/shepherd.scm?id=86b8869ffffad96e06e98d523f287b25684a6fa6'>linux-container: Remove '%containerized-shepherd-service' hack.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2019-04-23 16:38:11 +0200'>2019-04-23</span></td><td><a href='/guix/commit/gnu/services/shepherd.scm?id=95ef8b85b16f19557ea07d0d0cbf856f85657368'>services: shepherd: Support one-shot services.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2018-12-18 16:04:26 +0100'>2018-12-18</span></td><td><a href='/guix/commit/gnu/services/shepherd.scm?id=6ea6e1476ff4a18d4b4b864c3065d18ed99c69af'>file-systems: Spawn a REPL only when interaction is possible.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2018-09-26 23:40:36 +0200'>2018-09-26</span></td><td><a href='/guix/commit/gnu/services/shepherd.scm?id=a56c4eb8f43ae5555985d8a84308d150c0763c5a'>services: shepherd: Add workaround for 0.5.0 in containers.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2018-09-26 23:40:36 +0200'>2018-09-26</span></td><td><a href='/guix/commit/gnu/services/shepherd.scm?id=4245ddcbc9f935804c17c97872b90ec1050c2d75'>guix system: Load all services on reconfigure, not just stopped ones.</a><span class='msg-avail'>...</span></td><td>Carlo Zancanaro</td></tr>
<tr><td><span title='2018-07-13 00:08:54 +0200'>2018-07-13</span></td><td><a href='/guix/commit/gnu/services/shepherd.scm?id=701383081a9814d21823d42978ae23ee654e0427'>services: shepherd: Support custom actions.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2018-06-20 23:47:08 +0200'>2018-06-20</span></td><td><a href='/guix/commit/gnu/services/shepherd.scm?id=378daa8cb677121e1893f9173af1db060720d6e4'>services: boot: Take gexps instead of monadic gexps.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2018-03-15 11:34:57 +0100'>2018-03-15</span></td><td><a href='/guix/commit/gnu/services/shepherd.scm?id=88cd7bbd3dc8ecb6b02435338eff1524ad7154ed'>services: 'shepherd-service-type' now accepts a default value.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2018-01-21 00:24:02 +0100'>2018-01-21</span></td><td><a href='/guix/commit/gnu/services/shepherd.scm?id=33033a620e64d64bc549b4472e2f4db61e801d18'>services: shepherd: Make 'shepherd-configuration-file' non-monadic.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2017-05-03 16:16:17 +0200'>2017-05-03</span></td><td><a href='/guix/commit/gnu/services/shepherd.scm?id=69daee23af49aeafcb1d250c90860f9253da719e'>ui: Rename '_' to 'G_'.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2017-02-08 16:17:05 +0100'>2017-02-08</span></td><td><a href='/guix/commit/gnu/services/shepherd.scm?id=750a423996f3471aa4807609256f686c8ebf5584'>services: shepherd: Replace spaces with hyphens in file names.</a><span class='msg-avail'>...</span></td><td>Clément Lassieur</td></tr>
<tr><td><span title='2016-12-19 17:51:00 +0100'>2016-12-19</span></td><td><a href='/guix/commit/gnu/services/shepherd.scm?id=9fc037fe1099f499acc01c5f40cae7f72796c49a'>services: Use 'file-append' in more places.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>